Liying Colourful iPhone 4/4s External Rechargeable Backup Battery Charger Case Cover for for Iphone 4 with iPhone 4s cases (IPhone 4/4s 1900 METALLIC GRAY) High quality Ultra Slim External Li polymer battery Lithium-ion Power for iPhone 4 & 4S Standby Time:Up to 230 Hours;Weight: 65g; Talk Time:Up tp6.5 Hours on 3G Network / Up to 10 Hours on 2G Network; Audio Play:Up to 30 Hours;Vidio Play:Up to 8 Hours; Portable,convenient,easy to use,high capacity